Bottom hole weight indicator



SEARCH QM Jan. 20, 1959 M. A. GARRISON BOTTOM HOLE WEIGHT INDICATORFiled Feb. 28, 1955 f/GL/ INVENTOR.

MAR/ON A. CARR/SON ATTORNEYS United States Patent BOTTOM HOLE WEIGHTINDICATOR Marion A. Garrison, South Pasadena, Calif., assignor, by mesneassignments, to Johnston Testers, Inc., Houston, Tex., a corporation ofTexas Application February 28, 1955, Serial No. 491,028

4 Claims. (Cl. 73-151) This invention relates to a bottom hole weightindicator.

In the well industry it is common to apply weight to a tool by allowingsome of the weight of the well string to rest on the tool. The amount ofweight applied is measured by a weight indicator connected to the top ofthe string. However, this indication is not a true representation of theweight actually applied to the tool, since in a deep well the stringtends to corkscrew within the well and a considerable amount of theweight thereof is supported by frictional engagement with the bore wall.For example, if 10,000 pounds indicated at the top of the well isapplied in a well 10,000 feet deep, as much as 6,000 pounds may besupported by frictional engagement with the bore wall, leaving only4,000 pounds actually applied at the tool.

It is the principal object of this invention to provide a recordingweight indicator which may be incorporated in the well stringimmediately above the tool to be actuated, whereby a permanent record ofthe actual weight applied to the tool may be obtained.

The preferred form of my invention is described in the followingdetailed specification, and illustrated by way of example in theaccompanying drawings, wherein:

Figs. 1 and 2 show a longitudinal section taken through the upper andlower portions respectively of a tool embodying the principles of myinvention.

Fig. 3 is a sectional view of a fragment of the structure shown in Fig.1 drawn to an enlarged scale.

Fig. 4 is a sectional view taken on line 44 of Fig. 3.

Referring now to the drawings, wherein similar numerals are used todesignate the same elements throughout the various views shown,generally indicates a housing comprising upper and lower sections 11 and12, respectively. The housing sections 11 and 12 are threadedlyconnected together in the manner indicated at 13 and the upper end ofthe section 11 is adapted to be connected to the lower end of a drillstring by threads 14.

A tubular mandrel 15 is slidably received within the lower housingsection 12. Keys 16 mounted in the housing are slidably received insuitable splines in the mandrel to permit relative longitudinal whilepreventing rotational movement between the mandrel and housing in amanner well known in the art. A cap 17 is threaded onto the upper end ofthe mandrel. The lower end of the cap 17 is adapted to abut the upperend of the lower housing section 12 to limit the upward movement of thehousing relative to the mandrel.

The outer surface of the mandrel 15 and the inner wall of the housingsection 12 are each stepped outwardly adjacent their lower ends toprovide two opposing surfaces 18 and 19, respectively. As can best beseen in Fig. 1, the surfaces 18 and 19 are spaced from each other whenthe mandrel 15 is in its lowermost position relative to the housingsection 12 and define an annular chamber 20. A pair of O-ring seals 21and 22 are mounted in suitable grooves on the mandrel, one above and onebelow the chamber 20, in sealing engagement "ice with the inner wall ofthe housing section 12. An annular groove 23 is formed in the innersurface of the mandrel 15 below the chamber 20, and a plurality ofdownwardly and inwardly inclined drilled passageways 24 connect saidgroove with the chamber 20. An annular rubber ring 45 is confinedbetween the lower end of the housing section 12 and an upwardly facingexternal shoulder 46 on the mandrel 15 to prevent dirt and sand fromgetting between the mandrel and housing.

A connecting member, generally indicated at 25 and having an upstandingstem portion 26 and a lower bellshaped housing section 27, is threadedinto the lower end of the mandrel 15, as shown at 28, with the stemportion 26 extending upwardly therewithin and covering the annulargroove 23. A pair of O-ring seals 29 and 30 are mounted in suitablegrooves on the stem 26 and sealingly engage the inner wall of themandrel 15 above and below the annular groove 23. A plurality of drilledpassageways 31 in the stem 26 connect the groove 23 with the chamber 32within the bell-shaped housing 27. A pressure recorder 33 is threadedinto and closes the lower portion of the bell-shaped housing 27. Theannular chamber 20, passageways 24, the annular groove 23, passageways31 and the chamber 32 are filled with oil through a plugged orifice 34connected to the chamber 20, and the plug is then inserted to provide acompletely sealed system.

The specific details of the pressure recorder 33 form no part of theinstant invention. The recorder is any recorder capable of recording thefluid pressure within the chamber 32. For convenience, the recordershown is of the type described and claimed in my copending applicationentitled Tension Type Pressure Recorder, filed January 10, 1955, SerialNumber 480,707, now Patent No. 2,816,440.

A tubular sub 35 is threaded onto the lower end of the mandrel 15, asindicated at 36, and extends downwardly therefrom enclosing the pressurerecorder 33 but leaving an annular space 37 therebetween. The lower endof the sub 35 is connected to a second sub 38 at 39. The sub 38 isadapted to be connected at its lower end to a well tool not shown. Aspider assembly 40, having fluid passages 41 extending therethrough, isthreaded into the upper end of the sub 38 and acts to center the lowerend of the pressure recorder 33.

Circulation of the well fluid is provided by the central passage 42through the mandrel 15 which communicates with a counterbore 43 in theupper end of the stem 26. A plurality of lateral ports 44 connect thecounterbore 43 with the annular space between the bell-shaped housing 27and the inner wall of the sub 35.

In the operation of the device, the members are assembled as shown inFigs. 1 and 2 of the drawing. The lower end of the device is connectedto the upper end of a well tool and the upper end of the device isconnected to the well string. When weight is applied, the housing 10moves downwardly relative to the mandrel 15, applying pressure to theoil in chamber 20. The pressure in chamber 20 is communicated throughthe various passageways described to the fluid in the chamber 32 andactuates the pressure recorder 33. The pressure recorded by the pressurerecorder 33 is a direct measurement of the weight actually applied atthe tool.

While I have shown and described a specific embodiment of my invention,it is evident that various changes may be made in its construction bythose skilled in the art, without departing from the spirit of theinvention as defined in the appended claims.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. In a bottom hole weight indicator, a pair of telescopic membersincluding complementary portions forming a pressure chamber adapted tobe filled with a substantially incompressible fluid and having a volumedependent upon the relative positions of said members, pressureindicating means including a pressure-sensitive device mounted on one ofsaid members and in fluid communication with said pressure chamber,there being a passage in at least one of said members extending betweenan end portion of one of said members and an opposite end portion of theother of said members, and means for connecting the aforesaid endportions of said members to a well string and to a well tool,respectively.

2. In a bottom hole weight indicator, a tubular housing, means forconnecting the upper end of said housing to the lower end of a wellstring, a mandrel slidably positioned within the said housing forlimited longitudinal movement with respect thereto and extendingdownwardly therefrom, said mandrel and said housing includingcomplementary portions forming a hydraulic pressure chamber adapted tobe filled with a fluid and having a volume dependent upon the relativepositions of said housing and said mandrel, a pressure recorder securedto said mandrel, said mandrel having a passage therein connecting saidpressure recorder and said pressure chamber, and a tubular member forconnecting the lower end of said mandrel to a well tool, said mandrelhaving a passage extending from and adapted to provide fluidcommunication between said upper housing end and the interior of saidtubular member.

3. In a bottom hole weight indicator, a tubular housing, means forconnecting the upper end of said housing to the lower end of a wellstring, a mandrel slidably positioned within the said housing forlimited longitudinal movement with respect thereto and extendingdownwardly therefrom, said mandrel and said housing includingcomplementary opposed spaced shoulders forming a pressure chambertherebetween, said chamber being filled with a hydraulic fluid, apressure recorder secured to said mandrel, said mandrel having a passagetherein connecting said pressure recorder and said pressure chamber, anda tubular member for connecting the lower end of said mandrel to a welltool, said mandrel having a passage extending from and adapted toprovide fluid communication between said upper housing end and theinterior of said tubular member.

4, In a bottom hole weight indicator, a tubular housing, means forconnecting the upper end of said housing to the lower end of wellstring, a mandrel slidably positioned within the said housing forlimited longitudinal movement with respect thereto, said housing havinga downwardly facing internal shoulder, said mandrel having an upwardlyfacing external shoulder opposed to and spaced from said downwardlyfacing shoulder thereby forming a pressure chamber therebetween, saidchamber being filled with a hydraulic fluid, a pressure recorder securedto said mandrel, said mandrel having a passage therein connecting saidpressure recorder and said pressure chamber, and a tubular member forconnecting the lower end of said mandrel to a well tool, said mandrelhaving a passage extending from and adapted to provide fluidcommunication between said upper housing end and the interior of saidtubular member.

References Cited in the file of this patent UNITED STATES PATENTS1,080,937 Stephens Dec. 9, 1913 1,417,461 Eason May 23, 1922 1,993,796Morgan Mar. 12, 1935 2,422,806 Silverman et al. June 24, 1947

